The rotary brush or beater mounted for rotation in the nozzle portion of the take-up passageway of the suction or vacuum apparatus of the type mentioned is typically driven by a tensioned endless belt looped and offset at 90.degree. more or less by twisting so as to frictionally engage the brush or beater located circumferentially centrally thereof on the one hand, and the unsupported end of the motor driven shaft on the other hand, which shaft also drives the suction fan or impeller of the apparatus.
An access opening is provided in the wall of the housing surrounding and defining the take-up passageway, opposed to and in general axial alignment with the unsupported end of the driven shaft so that the requisite loop of the endless belt can be applied over same through such access opening or removed therefrom and withdrawn as the case may be.
Such access opening is provided with a closure member releasably secured to the surrounding housing so as to complete the housing defining the internal take-up passageway.
According to Dayton U.S. Pat. No. 2,616,115, with such an arrangement, when the brush or beater is forced to rotate through manipulation in a direction the reverse of its normal direction of rotation, the belt portion surrounding and bearing against the unsupported end portion of the motor driven shaft tends to creep axially outward along such portion and away from the motor housing until it becomes completely disengaged.
This may occur when the operator removes strands of material or fibres which have become wound around the brush or beater or when the brush or beater is supported upon a surface and displaced or propelled thereover to rotate same in a direction opposed to its normal direction which imparts reverse rotation to the motor driven shaft and consequent belt disengagement.
Proposals have been put forward to prevent such belt from riding off the motor driven shaft extremity.
One such embodiment is presented by MacFarland U.S. Pat. No. 3,049,744 which includes the provision of circumferentially extending flanges located at the extremity of the fan motor shaft and disposed perpendicularly to the shaft which will prevent advancement of the belt toward the unsupported shaft extremity.
An alternative resides in so contouring the shaft extremity as to provide a substantial enlargement and so effectively constrain the belt against dislodgement, as illustrated in Frame Canadian Pat. No. 376,639.
While the proposals of the prior art may prevent such belt from disengaging from or riding off the unsupported end of the driven shaft of the motor, by adopting same removal of the belt from the shaft or replacement is rendered very much more difficult.
Removal or replacement of such belt in the circumstances outlined will require the application of considerable force to stretch the belt so as to clear the obstruction, thereby increasing the possibility of potential injury to the fingers or the hand, and, as well, unnecessarily creating an inconvenience for the user and undue extension of the belt itself leading to deterioration.
Other patents, for example Erbor U.S. Pat. No. 3,437,424 and Brace U.S. Pat. No. 2,719,317, disclose belt lifting apparatus for disengaging the belt from the motor shaft and allowing for insertion and registration of a hose attachment directly within the fan chamber intake.